JP7424788B2 - Curable resin composition containing siloxane resin, cured film thereof, and method for producing siloxane resin - Google Patents

Description

The present invention relates to a curable resin composition using a siloxane resin containing a reactive group such as a 3,4-epoxycyclohexyl group, and a cured film obtained by curing the same.

Display elements such as liquid crystal display elements, organic electroluminescent elements (organic EL elements), electronic paper elements, etc. have protective films to prevent deterioration and damage to electronic components such as touch panels, and layers between wiring arranged in layers. A hardened film such as an interlayer insulating film to maintain insulation properties and a flattening film to increase the aperture ratio is provided. Conventionally, a transparent cured film (hereinafter also referred to as a protective film) is formed as a protective layer on the surface of a color filter used for manufacturing a color liquid crystal display (LCD). The protective film for color filters flattens the unevenness that occurs between the pixels of the color filter, improves the durability of the color filter against heat treatment and chemical treatment in post-processing, and improves the reliability of color LCD displays. Formed for the purpose of Protective films for color filters are required to have excellent flatness, heat resistance, chemical resistance, hardness, electrical reliability, transparency, and the like.

For example, regarding flatness, it is required to flatten the unevenness of about 1 to 2 μm in height, which is caused by overcoating the coloring composition when forming pixels, to 0.1 μm or less. Regarding heat resistance, high heat of about 200 to 270° C. may be applied when producing a transparent electrode such as ITO on a protective film by sputtering, and the protective film is required to be stable under this temperature condition. Regarding chemical resistance, stability of the protective film against acids, alkalis, solvents, etc. used in subsequent processes is required. Regarding adhesion, when manufacturing a liquid crystal display panel, substrates are sometimes bonded on a protective film, and it is required that the protective film at that location not peel off from the base. As for hardness, high hardness is required from the viewpoint of durability of the protective film. For electrical reliability, it is required that the insulating properties of the protective film be maintained and that impurities contained in the protective film do not contaminate the liquid crystal. Regarding transparency, the protective film is required to have no absorption in the visible light wavelength range so as not to impair the color characteristics of the color filter.

In addition to the above-mentioned required characteristics for the protective film, wide viewing angles and high-speed response are required as LCD panels become more sophisticated, and display systems similar to IPS (In-plane Switching) mode are being used. The characteristics required for the protective film are also becoming stricter. In display systems such as IPS mode, gaseous or liquid components and water generated or bled out from the color filter layer enter the liquid crystal layer via the protective layer, reducing the concentration of water and ionic impurities in the liquid crystal layer. If the amount increases or bubbles form in the liquid crystal, it will cause display defects. Therefore, in addition to preventing the impurity components mentioned above from passing through, low gas emission properties are particularly important because gas generation from the protective film that is in direct contact with the liquid crystal layer is directly linked to poor display. In addition, in recent years, there has been a demand for thinner LCD panels, so there is also a demand for thinner protective films, and the demand for flatness, which is the realization of flatness under the thin film, is also becoming more severe. . In other words, new challenges have arisen, such as achieving both low gas emissions and flatness.

Many compositions of epoxy and acrylic compounds have been proposed as materials for the protective film of color filters (Patent Documents 1 to 5, etc.), but they lack low gas emission and flatness. A material that simultaneously satisfies the required properties has not been found.
On the other hand, siloxane epoxy resins having 3,4-cyclohexyl groups (Patent Document 6) and materials using this material for forming cured films have also been proposed as materials for color filters (Patent Documents 7 to 9, etc.). ) do not focus on the siloxane structure in detail, and there is no discussion of low gas emission or flatness (Patent Documents 7 to 8, etc.).

International Publication No. 96/34303 Japanese Patent Application Publication No. 2000-103937 Japanese Patent Application Publication No. 2000-143772 Japanese Patent Application Publication No. 2001-091732 Japanese Patent Application Publication No. 2004-069930 WO2015/151957 Japanese Patent Application Publication No. 2005-338790 JP2012-241118A Japanese Patent Application Publication No. 2017-171748

The present invention is a siloxane resin-containing curable composition that has flatness, extremely low moisture absorption, and low gas emission, and is excellent in heat resistance, light resistance, chemical resistance, electrical reliability, and transparency. .

As mentioned above, the protective film for color filters satisfies the required characteristics of low moisture absorption, low gas emission, and flatness, and also has heat resistance, chemical resistance, hardness, electrical reliability, transparency, etc. Protective films for color filters must maintain a high degree of essential characteristics, and the scope of application of protective film materials that can satisfy these characteristics as compositions is becoming narrower.

Furthermore, in recent years, in addition to RGB, color filters (RGBW method) have been developed that have white (W) pixels that are not coated with a coloring composition for the color filter pixels, and the protective film is coated with the above-mentioned coloring composition. It is also required to satisfy flatness while filling the W space where no composition is applied. In other words, in addition to the conventional unevenness on pixels of about 1 to 2 μm, it is also required to flatten the larger concave space of 2 to 3 μm with a thin film of 2 μm or less in thickness on the colored pixel formation area. It is becoming more and more common.

The present invention has been made in view of the above-mentioned problems, and satisfies the required characteristics of flatness, low moisture absorption, and low gas emission, while improving heat resistance, chemical resistance, adhesion, hardness, and electrical reliability. Another object of the present invention is to provide a curable resin composition capable of forming a protective film with excellent transparency, a cured film obtained by curing the same, and a method for producing a siloxane resin used therein.

The present inventors conducted studies to solve the above-mentioned problems required for the protective film of color filters, and as a result, the above-mentioned problems were solved by a curable resin composition containing a siloxane resin having a specific structure. They discovered that it can be done and completed the present invention.

〔構造Ｔ１～Ｔ３中、Ｒは水素基、メチル基、エチル基又はフェニル基であり、Ｘは、次の(a)又は(b)であって、同一であっても異なっていてもよいが、各構造において少なくとも１つのＸは(a)である。
(a)グリシジル基、３，４－エポキシシクロヘキシル基、ビニル基、アクロイル基及びメタクリロイル基から選ばれるいずれかの反応性基、又は、炭素数１～６の有機基の末端に前記の反応性基を有する基
(b)炭素数１～６の有機基〕
〔２〕前記Ｘが、炭素数１～６の有機基の末端に３，４－エポキシシクロヘキシル基を有する基を含むことを特徴とする〔１〕に記載の硬化性樹脂組成物。
〔３〕前記シロキサン樹脂が、²⁹Si-ＮＭＲスペクトルにおいて、－９ｐｐｍ～－１３ｐｐｍにシグナルを示す下記の構造Ｄ１と－１５ｐｐｍ～－２４ｐｐｍにシグナルを示す下記の構造Ｄ２とを含有することを特徴とする〔１〕又は〔２〕に記載の硬化性樹脂組成物。

〔構造Ｄ１～Ｄ２中、Ｒは水素基、メチル基、エチル基又はフェニル基であり、Ｙは、前記の(a)又は(b)であって、各構造において同一であっても異なっていてもよい。〕
〔４〕前記硬化剤が、多価カルボン酸、多価カルボン酸の無水物、および多価カルボン酸の熱分解性エステルからなる群より選ばれる１種又は２種以上であることを特徴とする〔１〕～〔３〕のいずれかに記載の硬化性樹脂組成物。
〔５〕固形分の全質量に対して、前記シロキサン樹脂の固形分含有量が３質量％以上９９質量％以下であることを特徴とする〔１〕～〔４〕のいずれかに記載の硬化性樹脂組成物。
〔６〕シロキサン骨格を含まず、且つエポキシ基又は重合性不飽和結合を有する非シロキサン型化合物を含有することを特徴とする〔１〕～〔５〕のいずれかに記載の硬化性樹脂組成物。
〔７〕シロキサン骨格を含まず、且つエポキシ基又は重合性不飽和結合を有する非シロキサン型化合物が、下記式（４）で表されるエポキシ化合物であることを特徴とする〔６〕に記載の硬化性樹脂組成物。

〔式（４）中、Ａｒは炭素数６～１２の２価の芳香族炭化水素基である。また、Ａｒで表される２価の芳香族炭化水素基の水素原子の一部は、炭素数１～１０の炭化水素基、炭素数１～５のアルコキシ基又はハロゲン基で置換されていてもよい。ｌの平均値が０～２である。〕
〔８〕前記〔１〕～〔７〕のいずれかに記載の硬化性樹脂組成物を硬化させてなることを特徴とする、硬化物。
〔９〕下記(i)～(iii)を満足するシロキサン樹脂を製造する方法であって、
Ｓｉ(Ｘ₁)(ＯＲ₁)_３を加水分解又は加水分解縮合させるか、又はＳｉ(Ｘ₁)(ＯＲ₁)_３とＳｉ(Ｘ_２)_２(ＯＲ_４)_２とを加水分解又は加水分解縮合させることを特徴とするシロキサン樹脂の製造方法。
〔但し、Ｘ₁は、下記（ａ）に示す基であり、同一であっても異なっていてもよいが、少なくとも、炭素数１～６の有機基の末端に３，４－エポキシシクロヘキシル基を有する基を含有する。Ｘ_２は、下記（ａ）又は（ｂ）に示す基であり、同一であっても異なっていてもよいが、少なくとも、（ｂ）で示す基を有する。Ｒ₁およびＲ_４はそれぞれ独立に炭素数１～３のアルキル基又はフェニル基である。〕
(i) ²⁹Si-ＮＭＲスペクトルにおいて、－４７～－５２ppmにシグナルを示す下記の構造Ｔ１、－５５～－６１ppmにシグナルを示す下記の構造Ｔ２及び－６２～－７２ppmにシグナルを示す下記の構造Ｔ３を有し、シグナルの面積比は、Ｔ１：Ｔ２：Ｔ３＝０～１：１～１０：１～１００であること。
(ii) 重量平均分子量が７５０～２００００であること。
(iii) 下記（ａ）に含まれる反応性基１個あたりの分子量が３５０未満であること。

〔構造Ｔ１～Ｔ３中、Ｒは水素基、メチル基、エチル基又はフェニル基であり、Ｘは、次の(a)又は(b)であって、同一であっても異なっていてもよいが、各構造において少なくとも１つのＸは(a)である。
(a)グリシジル基、３，４－エポキシシクロヘキシル基、ビニル基、アクロイル基及びメタクリロイル基から選ばれるいずれかの反応性基、又は、炭素数１～６の有機基の末端に前記の反応性基を有する基
(b)炭素数１～６の有機基〕 That is, the gist of the present invention is as follows.
[1] A curable resin composition containing a siloxane resin that satisfies the following (i) to (iii), and a curing agent and/or a photocationic initiator.
(i) In ^{the 29} Si-NMR spectrum, the structure T1 below shows a signal between -47 and -52 ppm, the structure T2 below shows a signal between -55 and -61 ppm, and the structure below shows a signal between -62 and -72 ppm. T3, and the signal area ratio is T1:T2:T3=0-1:1-10:1-100.
(ii) The weight average molecular weight is 750 to 20,000.
(iii) The molecular weight per reactive group included in (a) below is less than 350.

[In structures T1 to T3, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and X is the following (a) or (b), which may be the same or different. , in each structure at least one X is (a).
(a) Any reactive group selected from glycidyl group, 3,4-epoxycyclohexyl group, vinyl group, acroyl group, and methacryloyl group, or the above-mentioned reactive group at the end of an organic group having 1 to 6 carbon atoms. a group having
(b) Organic group having 1 to 6 carbon atoms]
[2] The curable resin composition according to [1], wherein the X contains a group having a 3,4-epoxycyclohexyl group at the end of an organic group having 1 to 6 carbon atoms.
[3] The siloxane resin is characterized in that it contains the following structure D1 showing a signal at -9 ppm to -13 ppm and the following structure D2 showing a signal at -15 ppm to -24 ppm in the ²⁹ Si-NMR spectrum. The curable resin composition according to [1] or [2].

[In structures D1 and D2, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and Y is the above (a) or (b), which may be the same or different in each structure. Good too. ]
[4] The curing agent is one or more selected from the group consisting of polycarboxylic acids, anhydrides of polycarboxylic acids, and thermally decomposable esters of polycarboxylic acids. The curable resin composition according to any one of [1] to [3].
[5] The curing according to any one of [1] to [4], wherein the solid content of the siloxane resin is 3% by mass or more and 99% by mass or less based on the total mass of solids. resin composition.
[6] The curable resin composition according to any one of [1] to [5], which does not contain a siloxane skeleton and contains a non-siloxane compound having an epoxy group or a polymerizable unsaturated bond. .
[7] The non-siloxane compound that does not contain a siloxane skeleton and has an epoxy group or a polymerizable unsaturated bond is an epoxy compound represented by the following formula (4), according to [6] Curable resin composition.

[In formula (4), Ar is a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms. Furthermore, some of the hydrogen atoms of the divalent aromatic hydrocarbon group represented by Ar may be substituted with a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen group. good. The average value of l is 0 to 2. ]
[8] A cured product obtained by curing the curable resin composition according to any one of [1] to [7] above.
[9] A method for producing a siloxane resin that satisfies the following (i) to (iii), comprising:
Hydrolysis or hydrolytic condensation of Si(X ₁ )(OR ₁ ) ₃ or hydrolysis or hydrolysis of Si(X ₁ )(OR ₁ ) ₃ and Si(X ₂ ) ₂ (OR ₄ ) ₂ A method for producing a siloxane resin, which comprises condensation.
[However, X ₁ is a group shown in (a) below, which may be the same or different, but at least has a 3,4-epoxycyclohexyl group at the end of an organic group having 1 to 6 carbon atoms. Contains a group with X ₂ is a group shown in (a) or (b) below, and may be the same or different, but has at least a group shown in (b). R ₁ and R ₄ are each independently an alkyl group having 1 to 3 carbon atoms or a phenyl group. ]
(i) In the ²⁹ Si-NMR spectrum, the following structure T1 shows a signal at -47 to -52 ppm, the following structure T2 shows a signal at -55 to -61 ppm, and the following structure shows a signal at -62 to -72 ppm. T3, and the signal area ratio is T1:T2:T3=0-1:1-10:1-100.
(ii) The weight average molecular weight is 750 to 20,000.
(iii) The molecular weight per reactive group included in (a) below is less than 350.

[In structures T1 to T3, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and X is the following (a) or (b), which may be the same or different. , in each structure at least one X is (a).
(a) Any reactive group selected from glycidyl group, 3,4-epoxycyclohexyl group, vinyl group, acroyl group, and methacryloyl group, or the above-mentioned reactive group at the end of an organic group having 1 to 6 carbon atoms. a group having
(b) Organic group having 1 to 6 carbon atoms]

The curable resin composition according to the present invention satisfies the required characteristics of flatness, extremely low moisture absorption, and low gas emission, and is also suitable for use in display elements that have excellent heat resistance, chemical resistance, electrical reliability, and transparency. It is possible to form a cured film that can improve display performance, a display element equipped with this hardened film, and the above-mentioned cured film. The curable resin composition of the present invention can be applied not only as a protective film for color filters of LCDs including RGBW systems, but also for displays that require a transparent cured film with particularly excellent flatness and low gas emission properties. It can also be applied to devices. That is, it can be suitably applied as a component of organic EL display devices other than LCDs, μLED display devices, and display devices using quantum dots, especially when a transparent film that flattens unevenness or steps is required. It is. Furthermore, application to sensors such as CMOS equipped with a color filter layer is also possible. It can also be used publicly as an insulating film layer for semiconductor devices, multilayer printed wiring boards, touch panels, etc., especially when flatness is required. Furthermore, it is used for optical applications that require transparency, heat resistance, and low moisture absorption, etc., opto-device applications, mechanical parts materials, electrical and electronic parts materials, automobile parts materials, civil engineering materials, molding materials, paints and adhesives, etc. Widely used for various purposes.

The curable resin composition of the present invention contains a siloxane resin, a curing agent, and/or a photocationic initiator. Further, the curable resin composition may contain a surfactant, a solvent, and the like. Here, the siloxane resin refers to a resin having a siloxane bond (-Si-O-Si-), and in the present invention, it contains a siloxane resin having the following structure.

<Siloxane resin>
²⁹ The chemical shifts of the silicon-containing bond units T and D in the Si-NMR spectrum are observed in the range of -45 to -80 ppm for T unit and 0 to -40 ppm for D unit, but the siloxane resin of the present invention As a unit, signals are shown in the ranges of -47 to -52 ppm, -55 to -61 ppm, and -62 to -72 ppm, and these have the following structures T1 (-47 to -52 ppm) and T2 (- 55 to -61 ppm) and T3 (-62 to -72 ppm), which represent signals derived from silicon-containing bond units.

〔但し、Ｒは水素基、メチル基、エチル基、フェニル基であり、Ｘは、次の(a)又は(b)であって、同一であっても異なっていてもよいが、各構造において少なくとも１つのＸは(a)である。このＸについては後述する。
(a)グリシジル基、３，４－エポキシシクロヘキシル基、ビニル基、アクロイル基及びメタクリロイル基から選ばれるいずれかの反応性基、又は、炭素数１～６の有機基の末端に前記の反応性基を有する基
(b)炭素数１～６の有機基〕

[However, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and X is the following (a) or (b), which may be the same or different, but in each structure At least one X is (a). This X will be described later.
(a) Any reactive group selected from glycidyl group, 3,4-epoxycyclohexyl group, vinyl group, acroyl group, and methacryloyl group, or the above-mentioned reactive group at the end of an organic group having 1 to 6 carbon atoms. a group having
(b) Organic group having 1 to 6 carbon atoms]

The siloxane resin of the present invention is characterized in that it contains the above-mentioned T2 structure and T1 structure in addition to the signal indicating the T3 structure, which can be observed even in general siloxane resins. By having such T2 and T1 structures in addition to the T3 structure, it has heat resistance and chemical resistance derived from the T3 structure, as well as solubility in organic solvents and compatibility when used in combination with other resins. It becomes possible to improve the solubility, it is possible to design a wide range of required properties of the cured product, and it is also possible to apply it to various processing processes using curable resin compositions. For these structures T1 to T3, the signal area ratio is T1:T2:T3=0 to 1:1 to 10:1 to 100, preferably 0 to 1:1 to 10:1 to 50. It is good that

〔構造Ｄ１～Ｄ２中、Ｒは水素基、メチル基、エチル基又はフェニル基であり、Ｙは、前記の(a)又は(b)であって、各構造において同一であっても異なっていてもよい。〕 Furthermore, regarding the siloxane resin of the present invention, in addition to the above T structure, in the ²⁹ Si-NMR spectrum, the following structure D1 exhibits a signal from -9 ppm to -13 ppm and the following structure D1 shows a signal from -15 ppm to -24 ppm. It is preferable to contain structure D2. Having such a predetermined D1 structure and D2 structure is preferable because it improves compatibility with organic solvents and other epoxy resins.

[In structures D1 and D2, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and Y is the above (a) or (b), which may be the same or different in each structure. Good too. ]

Furthermore, the area ratio of the signals of the T structure and the D structure is preferably (T1+T2+T3):(D1+D2)=10 to 1:5 to 0. From the viewpoint of low hygroscopicity of the cured product, more preferably (T1+T2+T3):(D1+D2)=10-1:2-0. For example, if there is a need to increase heat resistance (low gas emission), it is necessary to design the siloxane resin to incorporate a large number of T structures. In addition, for example, if it is necessary to control the physical properties of the cured product and improve compatibility with other epoxy resins, it is necessary to design a siloxane resin that contains a certain amount of D structure. becomes.

A typical structure of the siloxane resin of the present invention includes a group represented by the following formula (1) or (2) in the molecule.

In the above formulas (1) and (2), j, k, m, n are
1≦j+k≦7 (j≧0, k≧1 ... (i)
2≦m+n≦100 (m≧1, n≧1) ... (ii)
is met. Here, j+k is preferably 1 or more from the viewpoint of compatibility with other compounds, and on the other hand, from the viewpoint of the chemical resistance and adhesion of the coating film, it is preferably 7 or less. That is, it is preferable to have an annular structure of an appropriate size that satisfies these characteristics. j+k is more preferably from 1 to 6, even more preferably from 1 to 4. Moreover, m+n is preferably 2 or more and 100 or less from the viewpoint of controlling the molecular weight and compatibility with other compounds. That is, the compound is preferably a compound in which a cyclic structure and a chain structure are combined in an appropriate ratio, and m+n is more preferably 2 to 99, and even more preferably 3 to 75. * represents a bond, and when connected, forms a Si-O-Si bond.

X in formula (1) and formula (2) is (a) or (b) described above, and may be the same or different, but includes one or more of (a). Note that (a) only needs to exist somewhere in X in the T structure or Y in the D structure, but it is possible for (a) to exist in multiple numbers and to exist in both the T structure and the D structure. preferable.

In the group having the reactive group described in (a) above at the end of the organic group having 1 to 6 carbon atoms, the "organic group having 1 to 6 carbon atoms" includes an alkyl group that may be branched, a cycloalkyl group, groups, phenyl groups, and the like. The number of carbon atoms is preferably 1 to 4, more preferably 1 to 3. Examples of such organic groups include alkyl groups such as methyl, ethyl, various propyl groups, and various butyl groups, and cycloalkyl groups such as cyclopropyl. Note that "various" means various isomers including n-, sec-, tert-, and iso-.

Furthermore, when X in formula (1) and formula (2) is a hydrocarbon group having 1 to 3 carbon atoms, a methyl group or an ethyl group is preferable.

The plurality of X's may be the same or different, but from the viewpoint of curability, one or more contains the reactive group of (a) above, and among these reactive groups, those having 1 to 6 carbon atoms It is preferable to contain a group having a 3,4-epoxycyclohexyl group at the end of the organic group of -Epoxycyclohexyl group-containing group accounts for 15 mol% or more, more preferably 30 mol% or more. The group having a 3,4-epoxycyclohexyl group at the end of the organic group having 1 to 6 carbon atoms is preferably a β-(3,4-epoxycyclohexyl)ethyl group.

ここで、式（３）中のＲ_Ｘは、水酸基、炭素数１～３の炭化水素基、フェニル基、メトキシ基、又はエトキシ基であり、Ｘは、前記した(a)又は(b)である。＊は結合手を表し、連結する場合はSi-O-Si結合を構成し、繰り返し単位が０～１５０００であることが好ましい。 On the other hand, R' in formula (1) and formula (2) is a hydroxyl group, a hydrocarbon group having 1 to 3 carbon atoms, a phenyl group, a methoxy group, an ethoxy group, or a group represented by the following formula (3). It is.

Here, R _X in formula (3) is a hydroxyl group, a hydrocarbon group having 1 to 3 carbon atoms, a phenyl group, a methoxy group, or an ethoxy group, and X is the above-mentioned (a) or (b). be. * represents a bond, and when connected, it constitutes a Si-O-Si bond, and the number of repeating units is preferably 0 to 15,000.

R' in formulas (1) and (2) may be the same or different, but if all R's are hydroxyl groups, storage stability may be poor, and depending on the formulation, the cured film may have low moisture absorption. Therefore, the content of hydroxyl groups is preferably 30 mol% or less based on 100 mol% of Si, and groups other than hydroxyl groups are more preferable.

Among the above R' and R _X , the hydrocarbon group having 1 to 3 carbon atoms is more preferably a methyl group or an ethyl group, whereby a cured film with high heat resistance can be obtained.

The weight average molecular weight of the siloxane resin is 750 to 20,000, and the molecular weight per reactive group contained in (a) is less than 350 g/eq.

Among these, the weight average molecular weight is expressed as a polystyrene equivalent weight average molecular weight (Mw) determined by gel permeation chromatography (GPC). A siloxane resin with an Mw of less than 750 results in a film (cured product) with a low crosslinking density and poor chemical resistance, and also tends to remain in the coating film as an unreacted substance, causing deterioration of the degassing properties of the coating film. If Mw is greater than 20,000, the flatness of a film (cured product) tends to deteriorate and the compatibility with other compounds tends to deteriorate. Preferably, Mw is 1000 to 15,000.

In addition, if the molecular weight per reactive group contained in (a) above is 350 g/eq or more, the content of reactive groups decreases, resulting in insufficient curability and a tendency for crosslinking density to decrease. , properties of the cured film such as chemical resistance deteriorate. Preferably, the molecular weight is 150 or more and less than 350. In addition, if all the reactive groups contain epoxy groups, the molecular weight will correspond to the epoxy equivalent.

The curable resin composition of the present invention forms a cured film with low hygroscopicity by containing the above-mentioned siloxane resins, especially siloxane epoxy resins, especially siloxane epoxy resins containing 3,4-epoxycyclohexyl groups. Obtainable. Although the details of this are not clear, the epoxy group of conventional general siloxane epoxy resins is a structural unit derived from highly hydrophilic glycidyl, whereas siloxane epoxy resins containing 3,4-epoxycyclohexyl groups The reason is presumed to be that it is a highly hydrophobic cyclohexyl epoxy group. Furthermore, when conventional general siloxane epoxy resins are manufactured by hydrolytic condensation, etc., silanol groups [groups representing hydroxyl groups in R' in formulas (1) and (2) above] are likely to be generated or remain. On the other hand, it is presumed that the reason is that the siloxane epoxy resin containing 3,4-epoxycyclohexyl groups in the present invention has fewer silanol groups.

The siloxane resin of the present invention can be produced, for example, by the method (A) or (B) below. That is,
(A) An alkoxysilane compound having a specific organic group or a mixture of an alkoxysilane having a specific organic group and another silane compound is hydrolyzed and polycondensed in the presence of an appropriate organic solvent, acid, and water. how to get it,
(B) It can be produced by known methods such as adding a compound having a specific organic group and a double bond group to polysiloxane having a hydrosilane structure, but method (A) is preferred because it is general and easy. .

When producing by method (A), a trialkoxysilane whose general formula is represented by Si(X ₁ )(OR ₁ ) ₃ is used as an alkoxysilane compound, and it is hydrolyzed or hydrolyzed and condensed, or An example of this is hydrolysis or hydrolytic condensation of this Si(X ₁ )(OR ₁ ) ₃ and a dialkoxysilane whose general formula is Si(X ₂ ) ₂ (OR ₄ ) ₂ . However, X ₁ is a group shown in (a) or (b) above, and may be the same or different, but one or more of them includes (a), and among (a), groups with 1 carbon number It is preferable that the organic group ˜6 contains a group having a 3,4-epoxycyclohexyl group at the end. X ₂ is a group shown in (a) or (b) above, and may be the same or different, and at least one group has a group shown in (b). R ₁ and R ₄ are each independently an alkyl group having 1 to 3 carbon atoms or a phenyl group.

For such a reaction, it is preferable to carry out hydrolytic condensation under acidic conditions, for example. Using organic or inorganic acids such as hydrogen fluoride, hydrochloric acid, nitric acid, formic acid, propionic acid, oxalic acid, citric acid, maleic acid, benzoic acid, malonic acid, glutaric acid, glycolic acid, methanesulfonic acid, toluenesulfonic acid, etc. be able to. Hydrolytic condensation requires the presence of water, and the amount of water may be at least a sufficient amount to hydrolyze the hydrolyzable groups of the silane compound, but preferably It is preferable to add it in an amount of 0.3 to 1.5 times the number (theoretical amount) by mole.

The above trialkoxysilane includes methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxy Silane, isobutyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxy Silane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriethoxysilane, p-styryltrimethoxysilane, p-styryltriethoxy Silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-octenyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, 2 -(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltripropoxysilane, 3,4-epoxycyclohexyl Examples include trialkoxysilanes such as methyltrimethoxysilane, 3,4-epoxycyclohexylmethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)methyltripropoxysilane. Among these, it is preferable to use trialkoxysilane having a 3,4-epoxycyclohexyl group.

Examples of the dialkoxysilane include dimethyldimethoxysilane, diethyldiethoxysilane, phenylmethyldimethoxysilane, diphenyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinylmethyldiethoxysilane, and 3-glycidoxysilane. Xypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl) ) Ethylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldipropoxysilane, 2-(3,4-epoxycyclohexyl)diethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)diethyldiethoxy Silane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, ethylmethyldimethoxysilane, ethylmethyldiethoxysilane, ethylmethyldipropoxysilane, 3-methacrylate Examples include dialkoxysilane compounds such as roxypropylmethyldimethoxysilane and 3-methacryloxypropylmethyldiethoxysilane.
Note that these trialkoxy or dialkoxy silane compounds can be used alone or in a mixture of two or more.

In the present invention, the content of the siloxane resin in the solid content of the curable resin composition is preferably 3% by mass or more, more preferably 8% by mass or more. Within the above range, the cured product will have a sufficiently low hygroscopicity. On the other hand, this upper limit is preferably 99% by mass or less, more preferably 95% by mass or less.

<Curing agent, photocationic initiator>
In addition to the siloxane resin, the curable resin composition of the present invention contains a curing agent (thermosetting agent) selected from the group consisting of polycarboxylic acids, anhydrides of polycarboxylic acids, and thermally decomposable esters of polycarboxylic acids. ), or a photocationic initiator or a combination thereof. By using these curing agents and/or photocationic initiators, the curable resin composition of the present invention can be cured into a cured film by heat, light irradiation, or a combination of heat and light irradiation.

Here, the polyhydric carboxylic acid used as a curing agent is a compound having two or more carboxy groups in one molecule, such as succinic acid, maleic acid, cyclohexane-1,2-dicarboxylic acid, cyclohexene-1, 2-dicarboxylic acid, cyclohexene-4,5-dicarboxylic acid, norbornane-2,3-dicarboxylic acid, phthalic acid, benzene-1,2,4-tricarboxylic acid, cyclohexane-1,2,4-tricarboxylic acid, benzene- Examples include 1,2,4,5-tetracarboxylic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, and butane-1,2,3,4-tetracarboxylic acid.

In addition, examples of polycarboxylic acid anhydrides used as curing agents include the above-mentioned polycarboxylic acid anhydrides, which may be intermolecular acid anhydrides, but are generally intramolecularly ring-closed acids. Anhydrous is used. An example of a preferred acid anhydride is trimellitic anhydride.

Furthermore, as the thermally decomposable ester of polycarboxylic acid as a curing agent, t-butyl ester, 1-(alkyloxy)ethyl ester, 1-(alkylsulfanyl)ethyl ester (but , the alkyl here represents a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, and such a hydrocarbon group may have a branched structure or a ring structure, and may be substituted with any substituent. may also be used).

Further, as the curing agent, a polymer or copolymer having two or more carboxy groups can also be used. The carboxy group of the above polymer or copolymer may be an anhydride or a thermally decomposable ester. Examples of such polymers or copolymers include polymers or copolymers containing (meth)acrylic acid as a constituent, copolymers containing maleic anhydride as a constituent, and tetracarboxylic dianhydrides. Examples include compounds in which acid anhydrides are ring-opened by reacting with diamines or diols.

On the other hand, examples of photocationic initiators include acid generators such as diazonium salts, iodonium salts, sulfonium salts, phosphonium salts, selenium salts, oxonium salts, and ammonium salt compounds. Examples of acid generators include the SunAid SI series from Sanshin Chemical Industry Co., Ltd., the CPI series from Sun-Apro Co., Ltd., the ADEKA Arkles SP series from ADEKA Co., Ltd., and the WPAG series from Fuji Film Wako Pure Chemical Industries, Ltd. . Further, auxiliary agents and sensitizers that are effective in combination with the photopolymerization initiator can be used in combination.

The curable resin composition of the present invention preferably contains such a curing agent and/or photocationic initiator in an amount of 1 to 40% by mass, and preferably 10 to 30% by mass, based on the total mass of the solid content of the composition. It is more preferably 10 to 20% by mass, and even more preferably 10 to 20% by mass. If it is less than 1% by mass, the curing reaction will not proceed sufficiently, and the cured product will not have sufficient physical properties such as insufficient heat resistance, and in particular, the non-siloxane type epoxy compound described below will be left in excess. If this happens, the adverse effect on gas generation will be greater. On the other hand, if it exceeds 40% by mass, the excess cured product that does not contribute to the curing reaction will have an adverse effect on gas generation, and the properties of the cured product may not be sufficiently obtained.

<Non-siloxane type compound>
The curable resin composition of the present invention can further contain a non-siloxane compound that does not contain a siloxane structure. Such a non-siloxane type compound can be used without any particular restriction as long as it is compatible with the above-mentioned siloxane resin, and by including it, properties such as flatness and hardness can be further improved. This is preferable because the viscosity can be adjusted. As such a non-siloxane type compound, a compound that does not contain a siloxane skeleton and has an epoxy group or a polymerizable unsaturated bond is used. Generally, when using a siloxane epoxy resin having an epoxy group as the siloxane resin of the present application, an epoxy compound that does not contain a siloxane skeleton is mainly used in combination, so an epoxy compound that does not contain a siloxane skeleton that is liquid at room temperature or solid at room temperature. As long as they can be mixed uniformly with the addition of a solvent, they can be used without particular restrictions.
In addition, when using a siloxane resin having a polymerizable unsaturated bond as the siloxane resin of the present application, there is no particular restriction as long as a compound having a polymerizable unsaturated bond that does not mainly contain a siloxane skeleton can be uniformly mixed with the addition of a solvent. Can be used. Specific compounds are illustrated below.

Examples of chain aliphatic epoxy compounds that are liquid at room temperature include trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, mono- or diglycidyl ether of branched alkyl esters, and the FOLDI series manufactured by Nissan Chemical. Such a chain aliphatic epoxy compound contributes to improving heat resistance by improving crosslink density through reaction with a curing agent. In particular, an epoxy compound having a viscosity of 30 to 500 mPa·s (25° C.) can be preferably used.

In addition, examples of alicyclic epoxy compounds that are liquid at room temperature include (3',4'-epoxycyclohexylmethyl)3,4-epoxycyclohexanecarboxylate, 2-(3,4-epoxy)cyclohexyl-5,1-spiro (3,4-epoxy)cyclohexyl-m-dioxane, bis(3,4-epoxycyclohexylmethyl)adipate, hydrogenated bisphenol A diglycidyl ether, 1,4-cyclohexanedimethanol-bis3,4-epoxycyclohexanecarboxylate Epoxy compounds having a viscosity of 50 to 3500 mPa·s (25°C) can be preferably used.

Furthermore, examples of aromatic epoxy compounds that are liquid at room temperature include low molecular weight compounds such as bisphenol A epoxy compounds and bisphenol F epoxy compounds.

Further, examples of the epoxy compound having a triazine skeleton that is liquid at room temperature include polyfunctional epoxy compounds having a triazine skeleton (manufactured by Nissan Chemical, TEPIC-PAS, TEPIC-VL, TEPIC-UC, etc.).

Among these epoxy compounds that are liquid at room temperature, low molecular weight liquid compounds such as (3',4'-epoxycyclohexylmethyl)3,4-epoxycyclohexane carboxylate and bisphenol A type epoxy resin can be more preferably used.

By using these liquid epoxy resins, the flatness of the film (cured product) can be further improved.

On the other hand, epoxy compounds that are solid at room temperature include bisphenol A epoxy compounds, bisphenol F epoxy compounds, phenol novolac epoxy compounds, cresol novolac epoxy compounds, glycidyl ethers of polyhydric alcohols, and glycidyl esters of polyhydric carboxylic acids. , alicyclic epoxy compounds such as 1,2-epoxy-4-(2-oxiranyl)cyclohexane adducts of 2,2-bis(hydroxymethyl)-1-butanol (for example, "EHPE3150" manufactured by Daicel), ) Copolymers of (meth)acrylic acid esters containing glycidyl acrylate as an essential component, epoxidized polybutadiene (for example, "NISSO-PB/JP-100" manufactured by Nippon Soda Co., Ltd.), trifunctional epoxy compounds having a triazine skeleton ( Known epoxy compounds that are solid at room temperature, such as TEPICSC-G, S, SS, SP (manufactured by Nissan Chemical Co., Ltd.), can be used without particular limitations. In addition, an ε-caprolactam modified product of (3',4'-epoxycyclohexylmethyl)3,4-epoxycyclohexanecarboxylate (TTA2081 manufactured by Tetrachem), which is an epoxy compound that is waxy or granular at room temperature and has a low melting point, TTA2083) etc. can also be used.

Among these, copolymers of two or more types of (meth)acrylic esters containing glycidyl (meth)acrylate as an essential component include, for example, glycidyl (meth)acrylate and (meth)acrylic esters and other polymerizable It is a compound obtained by radical copolymerization of unsaturated compounds by a conventional method. In the above radical copolymerization, known radical polymerization initiators such as azo compounds or peroxides can be used. Further, the degree of polymerization may be controlled using a known chain transfer agent or polymerization inhibitor so that the weight average molecular weight is 900 to 20,000.

Examples of (meth)acrylic esters other than glycidyl (meth)acrylate and other polymerizable unsaturated compounds used in the above copolymer are shown below, but the invention is not limited thereto.

(Meth)acrylic acid esters can be obtained by subjecting (meth)acrylic acid ((meth)acrylic acid refers to acrylic acid or methacrylic acid) to a condensation reaction with an alcohol (R ¹ OH) component. As the (R ¹ OH) component, any known component can be used without particular limitation. Specific examples of R ¹ include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group. group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, icosyl group, cyclopropyl group, cyclopentyl group, cyclopentylethyl group, cyclohexyl group , cyclohexylmethyl group, 4-methylcyclohexyl group, adamantyl group, isobornyl group, dicyclopentanyl group, dicyclopentenyl group, vinyl group, allyl group, ethynyl group, phenyl group, tolyl group, mesityl group, naphthyl group, anthryl group saturated or unsaturated monovalent hydrocarbon groups such as phenanthryl, benzyl, 2-phenylethyl, and 2-phenylvinyl groups, and pyridyl, piperidyl, piperidino, pyrrolyl, pyrrolidinyl groups , an imidazolyl group, an imidazolidinyl group, a furyl group, a tetrahydrofuryl group, a thienyl group, a tetrahydrothienyl group, a morpholinyl group, a morpholino group, and a quinolyl group. The above hydrocarbon group or heterocyclic group, etc. may be a halogen atom, a carbonyl group, a thiocarbonyl group, a nitro group, a silyl group, an ether group, a thioether group, an ester group, a thioester group, a dithioester group, or a urethane group. , a thiourethane group, a ureido group, a thioureido group, or the like may be introduced as a substituent. Such a monovalent group may be appropriately selected depending on the structure of the target (meth)acrylic acid ester copolymer, but from the viewpoint of performance and economical efficiency, a saturated group having 1 to 20 carbon atoms may be used. Alternatively, it is preferably an unsaturated monovalent hydrocarbon group, and more preferably a saturated or unsaturated monovalent hydrocarbon group having 1 to 6 carbon atoms. Note that the saturated or unsaturated monovalent hydrocarbon group may be a hydrocarbon group having a branched structure or a ring structure, and may further be substituted with an arbitrary substituent. However, the above substituent preferably does not have a reactive structure such as an acidic group or an amide bond.

Other polymerizable unsaturated compounds include styrene and its derivatives, and specific examples include styrene, α-methylstyrene, or the aromatic ring of styrene in which alkyl groups, halogen atoms, hydroxyl groups, etc. are introduced. Compounds can be used.

In addition to the above, epoxy group-containing polymerizable unsaturated compounds other than glycidyl methacrylate (for example, glycidyl acrylate, (meth)acrylic acid [4-(glycidyloxy)butyl], (meth)acrylic acid [(3,4 -epoxycyclohexyl)methyl] and 4-(glycidyloxymethyl)styrene), and alkoxysilyl group-containing polymerizable unsaturated compounds (such as (meth)acrylic acid [3-(trimethoxysilyl)propyl], (meth)acrylic acid [3-(trimethoxysilyl)propyl], ) Acrylic acid [3-(triethoxysilyl)propyl], 4-(trimethoxysilyl)styrene, etc.) may be copolymerized.

Among the copolymers exemplified above, preferred examples include those copolymerized with glycidyl methacrylate, alkyl methacrylate esters (C1 to C4 alkyl groups), and those copolymerized with styrene. Examples include those having a softening point (Tg) of 10 to 90°C. A more preferable range of Tg of the copolymer is 40 to 90°C.

Among the above-mentioned epoxy compounds that are solid at room temperature, from the viewpoint of further improving heat resistance and low gas-emitting properties, compounds with an average value of 1 of 0 to 2, represented by the following general formula (4), are particularly preferred. It is an epoxy compound.

In the general formula (4), Ar is a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms. Further, some of the hydrogen atoms of the divalent aromatic hydrocarbon group represented by Ar are substituted with a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen group. Good too.

The epoxy compound of general formula (4) may be a bisphenolfluorene type epoxy compound or a bisnaphtholfluorene type epoxy compound. This epoxy compound has relatively little effect on the viscosity of the curable resin composition, and is an effective component in imparting low gas emission and heat resistance. In particular, in order to impart low gas emission properties, bisnaphtholfluorene type epoxy resins are more preferred.

l in general formula (4) may have an average value of 0 to 2; if it is 0 or more, it can increase solubility, and if it exceeds 2, it tends to affect the curability of the cured film. . The average value of l is preferably 0.01 to 1.
The average value of l can be calculated from the epoxy equivalent; for example, in the case of a bisnaphtholfluorene type epoxy compound,
(Epoxy equivalent) x 2 = (average value of l) x 506.6 + 562.7
It can be calculated from, and in the case of bisphenol fluorene type epoxy compounds,
(Epoxy equivalent) x 2 = (average value of l) x 406.5 + 462.5
It can be calculated from

This epoxy compound of general formula (4) can be synthesized by a known method such as the method described in JP-A-9-328534, but it can be synthesized by 9,9-bis(4-hydroxyphenyl)fluorene or The most common and preferred method is to condense ,9-bis(4-hydroxynaphthyl)fluorene and epichlorohydrin in the presence of an alkali. The value of l can be set to a desired value by adjusting the molar ratio of raw material compounds during synthesis or adjusting the reaction conditions.

Next, compounds having polymerizable unsaturated bonds that do not contain a siloxane skeleton will be exemplified. An epoxy acrylate compound obtained by reacting the above-mentioned epoxy compound that does not contain a siloxane skeleton with acrylic acid, methacrylic acid, etc., which are monocarboxylic acid compounds having a polymerizable unsaturated bond, is uniformly added with a solvent. As long as they can be mixed, they can be used without particular restrictions. Other examples of monocarboxylic acid compounds having a polymerizable unsaturated bond include half esters of 2-hydroxyethyl (meth)acrylate and succinic anhydride, and 2-hydroxyethyl (meth)acrylate and succinic anhydride, where (meth)acrylate represents acrylate or methacrylate. Examples include a half ester of hydroxyethyl (meth)acrylate and phthalic anhydride, a half ester of 2-hydroxyethyl (meth)acrylate and cyclohexane-1,2-dicarboxylic anhydride, and 4-vinylbenzoic acid.
Furthermore, polymerizable monomers having polymerizable unsaturated bonds can also be used without particular limitations as long as they can be mixed uniformly with the addition of a solvent.
Examples of polymerizable monomers include (meth)acrylic acid esters having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, and ethylene. Glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, Trimethylolethane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, glycerol(meth)acrylate, sorbitol penta (meth)acrylate, dipentaerythritol penta(meth)acrylate, or dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, alkylene oxide-modified hexa(meth)acrylate of phosphazene, caprolactone-modified dipentaerythritol hexa(meth)acrylate ) (meth)acrylic esters such as acrylate, and one or more of these can be used.

<Other ingredients>
Further, in the curable resin composition of the present invention, known compounds that promote curing, known as epoxy compound curing accelerators, curing catalysts, latent curing agents, etc., can be used, if necessary. When using a compound that accelerates curing, it is preferably blended in an amount of 0.01 to 2% by mass, and preferably 0.05 to 1.5% by mass, based on the total solid mass of the composition. It is more preferable that there be. If it is less than 0.01% by mass, it will lack effectiveness as an accelerator, and if it exceeds 2% by mass, sufficient storage stability may not be obtained when the curable resin composition is made into a solution, or it may not be as effective as an accelerator when heated. may have a negative effect on the coloring.

Examples of the compound that promotes curing include tertiary amines, quaternary ammonium salts, tertiary phosphines, quaternary phosphonium salts, borate esters, Lewis acids, organometallic compounds, and imidazoles. In particular, 1,8-diazabicyclo[5.4.0]undec-7-ene or 1,5-diazabicyclo[4.3.0]non-5-ene or salts thereof are preferred.

Furthermore, the curable resin composition of the present invention can contain a solvent. Known compounds can be used as the solvent, such as ester solvents (butyl acetate, cyclohexyl acetate, etc.), ketone solvents (methyl isobutyl ketone, cyclohexanone, etc.), ether solvents (diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, etc.) ), alcohol solvents (3-methoxybutanol, ethylene glycol mono-t-butyl ether, etc.), aromatic solvents (toluene, xylene, etc.), aliphatic solvents, amine solvents, amide solvents, etc. Can be used without restrictions. From a safety point of view, ester or ether solvents with a propylene glycol skeleton, such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, propylene glycol monomethyl Ether acetate, propylene glycol monoethyl ether acetate, propylene glycol diacetate, and the like are preferred. Also preferred are 3-methoxybutyl acetate, 3-methoxy-3-methylbutyl acetate, and 1,3-butylene glycol diacetate, which have structures similar to these.

There is no particular restriction on the solid content concentration of the curable resin composition of the present invention, but for example, for use as a protective film for color filters, it is recommended that the solid content concentration, which is the total amount of components other than the solvent, be 10 to 30% by mass. Generally, it is adjusted within a range. In addition, in order to improve the flatness of the protective film of the color filter, 40 to 90% by mass of a solvent with a boiling point of less than 150°C at normal pressure and 10 to 60% by mass of a solvent with a boiling point of 150°C or higher at normal pressure are used in combination. It is preferable to control the drying properties of the curable resin composition.

The curable resin composition of the present invention has a total content of a siloxane resin and a non-siloxane compound that satisfies (i) to (iii), that is, a content of the curable resin, of 55 to 55% of the total mass of the solid content. It is preferably 95% by mass, more preferably 60 to 80% by mass. If the content of the curable resin is less than 55% by mass, the ratio of the curing agent to the curable resin becomes large, and the properties of the curable resin as a cured product may not be sufficiently obtained or it will not contribute to the curing reaction. Excess cured material may adversely affect gas generation. In addition, if the content of the curable resin exceeds 95% by mass, the ratio of the curing agent to the curable resin will be extremely small, and the curing reaction will not proceed sufficiently, resulting in a lack of heat resistance of the cured product. Become.

The curable resin composition of the present invention may further contain other arbitrary components as necessary, such as colorants, fillers, resins, additives, and the like. Here, dyes, organic pigments, inorganic pigments, carbon black pigments, etc. are used as colorants, silica, talc, etc. are used as fillers, and vinyl resins, polyester resins, polyamide resins, polyimide resins, polyurethane resins, polyethers are used as resins. resin, melamine resin, etc., and additives such as dispersants, surfactants, silane coupling agents, viscosity modifiers, wetting agents, antifoaming agents, antioxidants, ultraviolet absorbers, thermal radical initiators, etc. can be mentioned. As these optional components, known compounds can be used without particular limitation. When used as a protective film for color filters, surfactants (fluorosurfactants, silicone surfactants, etc.) may be used, however, the total content of the surfactants may exceed the total content of the curable resin composition. The upper limit is preferably 10% by mass based on the solid content. Examples of coupling agents include silane coupling agents (3-(glycidyloxy)propyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-ureidopropyltriethoxysilane). etc.), titanium-based coupling agents, aluminum-based coupling agents, etc. can be used. As a thermal radical initiator, azo such as 2,2-azobisisobutyronitrile, dimethyl 2,2-azobis2-methylpropionate, 1,1'-azobis(1-acetoxy-1-phenylethane), etc. Examples include system initiators and peroxides such as benzoyl peroxide.

As a method for producing a cured product of the curable resin composition of the present invention, known methods can be used. For example, after coating or injecting the curable resin composition onto a suitable base material or mold depending on the purpose or use, the solvent may be removed and the composition may be cured by heating. Drying under reduced pressure or the like can also be applied to remove the solvent.

The cured product of the curable resin composition of the present invention can be a cured film. The cured film can be produced as a protective film for a color filter by applying it to the surface of a pixel coloring composition applied to a base material of a color filter and curing the composition. At this time, in addition to RGB, when producing a color filter having white (W) pixels on which no coloring composition for pixels of the color filter is applied, the curable resin composition of the present invention is applied and cured. When the protective film is prepared, it fills the W space with a depth of about 1.0 to 3.0 μm that was formed because the coloring composition was not applied, and then coats the RGB coloring composition applied to the base material. The flatness between the surface of the formed protective film and the surface of the protective film formed on the W space can be satisfied.

The cured product of the curable resin composition of the present invention can not only be applied as a protective film for color filters of LCDs including RGBW systems, but also requires a transparent cured film with particularly excellent flatness and low gas emission properties. It is also possible to apply the present invention to a display device. That is, it can be suitably applied as a component of organic EL display devices other than LCDs, μLED display devices, and display devices using quantum dots, especially when a transparent film that flattens unevenness or steps is required. It is. Furthermore, application to sensors such as CMOS equipped with a color filter layer is also possible. In addition, the cured product of the curable resin composition of the present invention can improve the surface flatness while filling the holes in the step portions as described above, so it can be used in solder resist layers, plating resist layers, etching resist layers. resist layers such as, interlayer insulation layers such as multilayer printed wiring boards, gas barrier films, encapsulants for lenses and semiconductor light emitting devices such as light emitting diodes (LEDs), top coats for paints and inks, hard coats for plastics. It can also be used as a rust preventive film for metals. Moreover, it is extremely useful not only as a coating agent, but also because it can be applied to the production of films, substrates, plastic parts, optical lenses, etc. by molding the curable resin composition itself.

Hereinafter, embodiments of the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited thereto.

[Weight average molecular weight (Mw)]
Mw was measured by gel permeation chromatography (GPC) under the following conditions.
Equipment: HLC-8020 manufactured by Tosoh Corporation
Mobile phase: Tetrahydrofuran Column temperature: 40°C
Flow rate: 0.6mL/min Sample concentration: 1.0% by mass
Sample injection volume: 20μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[ ²⁹ Si-NMR measurement conditions]
Device name: JNM-ECA400 manufactured by JEOL Ltd.
Observation nucleus: ²⁹ Si
Observation frequency: 79.43MHz
Measurement temperature: room temperature Measurement solvent: CDCl ₃
Pulse width: 8.75μsec (90°)
Pulse repetition time: 5.0sec
Integration number: 11,000 times Sample concentration (sample/measurement solvent/relaxation reagent): 200mg/0.7ml/10mg
Relaxation reagent: Cr(acac) ₃

<Synthesis of siloxane epoxy resin>
[Synthesis example 1]
In a reaction vessel equipped with a stirring device, a dropping funnel, a thermometer, and a stirrer, 25.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 150.0 g of toluene were charged, and after completely dissolving them, they were added as an acidic catalyst. 1.25 g of p-toluenesulfonic acid monohydrate was further mixed and stirred at room temperature for 30 minutes. Further, 3.3 g of water was added dropwise and stirred for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous NaHCO ₃ solution, dried with MgSO ₄ and filtered, and the volatiles were removed under reduced pressure to obtain 18.8 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 250 g/eq. Mw was 4100 (siloxane epoxy resin A-1).

[Synthesis example 2]
In a reaction vessel equipped with a stirrer, a dropping funnel, a thermometer, and a stirrer, 20.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 5 g of 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane were added. After completely dissolving the mixture, 1.25 g of p-toluenesulfonic acid monohydrate was added as an acidic catalyst, and the mixture was stirred at room temperature for 30 minutes. Further, 3.1 g of water was added dropwise and stirred for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous NaHCO ₃ solution, dried with MgSO ₄ and filtered, and the volatiles were removed under reduced pressure to obtain 20.3 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 270 g/eq. Mw was 3200 (siloxane epoxy resin A-2).

[Synthesis example 3]
In a reaction vessel equipped with a stirrer, a dropping funnel, a thermometer, and a stirrer, 12.5 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 12. After completely dissolving 5 g of toluene and 150.0 g of toluene, 1.25 g of p-toluenesulfonic acid monohydrate was further mixed as an acidic catalyst, and the mixture was stirred at room temperature for 30 minutes. Furthermore, 3.0 g of water was added dropwise and stirred for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous NaHCO ₃ solution, dried with MgSO ₄ and filtered, and the volatiles were removed under reduced pressure to obtain 19.7 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 230 g/eq. Mw was 5000 (siloxane epoxy resin A-3).

[Synthesis example 4]
In a reaction vessel equipped with a stirrer, a dropping funnel, a thermometer and a stirrer, 7.5 g of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and 17 g of 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane were added. After completely dissolving 1.25 g of p-toluenesulfonic acid monohydrate as an acidic catalyst, the mixture was stirred at room temperature for 30 minutes. Further, 2.6 g of water was added dropwise and stirred for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous NaHCO ₃ solution, dried with MgSO ₄ and filtered, and the volatiles were removed under reduced pressure to obtain 19.7 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 290 g/eq. Mw was 3800 (siloxane epoxy resin A-4).

[Synthesis example 5]
In a reaction vessel equipped with a stirring device, a dropping funnel, a thermometer, and a stirrer, 25.0 g of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and 15.0 g of toluene were charged, and after completely dissolving them, they were added as an acidic catalyst. 1.25 g of p-toluenesulfonic acid monohydrate was further mixed and stirred at room temperature for 30 minutes. Furthermore, 2.8 g of water was added dropwise and stirred for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous NaHCO ₃ solution, dried with MgSO ₄ and filtered, and the volatiles were removed under reduced pressure to obtain 20.1 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 340 g/eq. Mw was 3500 (siloxane epoxy resin A-5).

[Synthesis example 6]
A reaction vessel equipped with a stirring device, a dropping funnel, a thermometer, and a stirrer was charged with 12.5 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 12.5 g of dimethyldiethoxysilane, and 150.0 g of toluene. After dissolving in the solution, 1.25 g of p-toluenesulfonic acid monohydrate as an acidic catalyst was further mixed and stirred at room temperature for 30 minutes. Furthermore, 3.7 g of water was added dropwise and stirred for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous NaHCO ₃ solution, dried with MgSO ₄ and filtered, and the volatiles were removed under reduced pressure to obtain 20.0 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 310 g/eq. Mw was 2900 (siloxane epoxy resin A-6).

[Synthesis example 7]
In a reaction vessel equipped with a stirrer, a dropping funnel, a thermometer, and a stirrer, 15.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 5.0 g of dimethyldiethoxysilane, and 5.0 g of methacryloxypropyltrimethoxysilane were added. After completely dissolving the mixture, 1.25 g of p-toluenesulfonic acid monohydrate was added as an acidic catalyst, and the mixture was stirred at room temperature for 30 minutes. Furthermore, 3.5 g of water was added dropwise and stirred for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous NaHCO ₃ solution, dried with MgSO ₄ and filtered, and the volatiles were removed under reduced pressure to obtain 20.0 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 260 g/eq. Mw was 2000 (siloxane epoxy resin A-7).

[Comparative synthesis example 1]
25.0 g of (3-glycidoxypropyl)trimethoxysilane, 100.0 g of toluene, and 50.0 g of 2-propanol (IPA) were placed in a reaction vessel equipped with a stirring device, a dropping funnel, a thermometer, and a stirrer. After dissolving, 7.5 g of a 5% aqueous tetramethylammonium hydroxide solution (TMAH aqueous solution) was added as a basic catalyst, and the mixture was stirred at room temperature for 24 hours. After the reaction was completed, the organic layer was washed with an aqueous citric acid solution, dried over MgSO ₄ and filtered, and then the volatiles were removed under reduced pressure to obtain 20.4 g of a transparent viscous resin. The epoxy equivalent of the obtained resin was 169 g/eq, and the Mw was 28,000 (siloxane epoxy resin a-1)

(Preparation of curable resin composition)
The compositions shown in Tables 1 to 5 were blended and stirred and mixed at room temperature for 3 hours to dissolve the solid components in the solvent to produce a curable resin composition. The numerical values of the composition are parts by mass, and the total solid content is 100 parts by mass.

The components used in the formulation of Examples and Comparative Examples as curable resin compositions are shown below.
<Siloxane epoxy resin>
A-1: Siloxane epoxy resin prepared in Synthesis Example 1 A-2: Siloxane epoxy resin prepared in Synthesis Example 2 A-3: Siloxane epoxy resin prepared in Synthesis Example 3 A-4: Siloxane prepared in Synthesis Example 4 Epoxy resin A-5: Siloxane epoxy resin prepared in Synthesis Example 5 A-6: Siloxane epoxy resin prepared in Synthesis Example 6 A-7: Siloxane epoxy resin prepared in Synthesis Example 7 A-8: 2-(3, Condensate of 4-epoxycyclohexyl)ethyltrimethoxysilane and dimethyldimethoxysilane (“6730D” manufactured by Tsunebashi Sangyo, epoxy equivalent 295/eq, Mw: 4,500)
a-1: Siloxane epoxy resin prepared in Comparative Synthesis Example 1 (epoxy equivalent: 169 g/eq, Mw: 28,000)
a-2: Siloxane epoxy resin having an epoxycyclohexyl group (“X-40-2669” manufactured by Shin-Etsu Chemical, epoxy equivalent: 191 g/eq, Mw: 383)
a-3: Siloxane epoxy resin having an epoxycyclohexyl group (“KR-470” manufactured by Shin-Etsu Chemical, epoxy equivalent: 200 g/eq, Mw: 737)
a-4: Siloxane epoxy resin having a methoxy group, an ethoxy group, and a glycidyl group ("X-41-1059A" manufactured by Shin-Etsu Chemical, epoxy equivalent: 350 g/eq, Mw: 2,500)
a-5: Siloxane epoxy resin that has an epoxycyclohexyl group but no hydroxyl, methoxy, ethoxy, or phenoxy group (“POLY200” manufactured by Arakawa Chemical Industries)

²⁹ Si-NMR measurements were performed on the siloxane epoxy resin components used in the formulation under the above conditions using a nuclear magnetic resonance apparatus (JNM-ECA 400 manufactured by JEOL Ltd.), and the results showed that components A-1 to A-8 were found. For components a-1 and a-4, signals were observed at 47 to -52 ppm, -55 to -61 ppm, and -62 to -72 ppm, which are derived from the structures T1, T2, and T3. In components A-2, 4, 6, and 7, -6 ppm to -13 ppm and -15 ppm to -24 ppm signals derived from the structures D1 and D2 were further observed.
The area ratio of each signal was T1:T2:T3=1:7:15 and D1:D2=4:26 for A-8.

<Curing agent, photocationic initiator>
B-1: Trimellitic anhydride B-2: Cyclopentanetetracarboxylic dianhydride B-3: Aromatic sulfonium salt-based ADEKA optomer "SP-170" (manufactured by ADEKA Co., Ltd.)

<Non-siloxane type epoxy compound containing no siloxane structure>
C-1: Bisphenol A type epoxy resin [YD-011 manufactured by Nippon Steel Chemical & Materials Co., Ltd., epoxy equivalent 450-500/eq]
C-2: Fluorene type epoxy resin [manufactured by Nippon Steel Chemical & Materials Co., Ltd., ESF-300C, epoxy equivalent 220-240/eq]
C-3: 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (manufactured by Daicel Corporation, EHPE3150, epoxy equivalent: 170 to 190 g/eq )
C-4: Glycidyl methacrylate copolymer with a copolymerization composition of glycidyl methacrylate: methyl methacrylate: n-butyl methacrylate = 5:3:2, epoxy equivalent: 295 g / eq)

<Curing accelerator>
E-1: Octylate of 1,8-diazabicyclo[5.4.0]undec-7-ene

<Coupling agent>
F-1: 3-(glycidyloxy)propyltrimethoxysilane

<Other ingredients>
S-1: Fluorine surfactant (Megafac F-556, manufactured by DIC Corporation)
<Solvent>
U-1: Propylene glycol monomethyl ether acetate (PGMEA)
U-2: Methyl 3-methoxypropionate (MMP)
U-3: Diethylene glycol ethyl methyl ether (EDM)

(Evaluation of curable resin composition: flatness)
A color filter substrate was prepared in which a black matrix, red, green, and blue pixels and a mosaic pattern with no blue pixels were formed, and irregularities of 2.5 μm in height were formed on the pixels. The above curable resin composition was applied to a color filter substrate using a spin coater, and dried on a 90° C. hot plate for 2 minutes to prepare a test piece. At this time, the coating conditions (spin rotation speed) were adjusted so that a cured film with a thickness of 1.5 μm was obtained on the pixels. Next, the test piece was baked in a hot air oven at 230°C for 30 minutes to obtain a cured film of the curable resin composition.

The height of the unevenness at two arbitrarily selected points on the surface of the cured film formed to protect the pixels was measured using a contact surface roughness meter (product name: Micro-shape measuring instrument ET- manufactured by Kosaka Institute Co., Ltd.) 4000A), and a three-level evaluation was performed based on the following criteria.
◎ (Good): Difference in height of unevenness is 0.10 μm or less. ○ (Slightly good): Difference in height of unevenness is more than 0.10 μm and less than 0.15 μm. △ (Slightly poor): Difference in height of unevenness is less than 0.10 μm. More than 0.15μm and less than 0.20μm × (defective): Difference in height of unevenness exceeds 0.2μm

(Evaluation of curable resin composition: Hygroscopicity)
The above-mentioned curable resin composition was applied onto a non-alkali glass substrate using a spin coater and dried on a 90° C. hot plate for 2 minutes to prepare a test piece. At this time, the coating conditions (spin rotation speed) were adjusted so that a cured film with a thickness of 1.5 μm was obtained. Next, the test piece was baked in a hot air oven at 230°C for 30 minutes to obtain a cured film of the curable resin composition. Next, this cured film-coated substrate was left standing for 24 hours at 85° C. and 85% RH in a constant temperature chamber (Environmental Tester SH-221 manufactured by Espec) to absorb moisture. 10 mg of the cured film of this test piece was scraped off and sampled, and the temperature was raised from room temperature to 150°C at a rate of 10°C/min in a nitrogen atmosphere and held at 150°C for 20 minutes.The amount of weight loss due to moisture absorption of the film was measured. Weight changes were measured using a thermogravimetric analyzer (trade name: Thermo plus EVO2, manufactured by Rigaku Co., Ltd.), and evaluated in three stages based on the following criteria.
◎ : Weight loss is less than 0.5% ○ : Weight loss is 0.5% or more and less than 2% △ : Weight loss is 2% or more and less than 3% × : Weight loss is 3% or more

(Evaluation of curable resin composition: Gas generation)
The above-mentioned curable resin composition was applied onto a non-alkali glass substrate using a spin coater and dried on a 90° C. hot plate for 2 minutes to prepare a test piece. At this time, the coating conditions (spin rotation speed) were adjusted so that a cured film with a thickness of 1.5 μm was obtained. Next, the test piece was baked in a hot air oven at 230°C for 30 minutes to obtain a cured film of the curable resin composition. 10 mg of the cured film of the test piece was scraped off and sampled, and the temperature was raised from room temperature to 120°C at a rate of 10°C/min under air flow, held at 120°C for 30 minutes, and then heated from 120°C to 230°C at 10°C/min. The weight loss upon holding at 230° C. for 3 hours was measured using a thermogravimetric analyzer (product name: Thermo plus EVO2, manufactured by Rigaku Co., Ltd.), and a three-level evaluation was performed based on the following criteria.
◎ : Weight loss is less than 5% ○ : Weight loss is 5% or more and less than 7% △ : Weight loss is 7% or more and less than 10% × : Weight loss is 10% or more

(Evaluation of curable resin composition: chemical resistance)
Test pieces on which a cured film of the curable resin composition was formed in the same manner as in the above hygroscopicity evaluation were immersed in N-methylpyrrolidone for 30 minutes at 40°C (NMP treatment) and in 18% hydrochloric acid aqueous solution at 25°C. After being immersed for 60 minutes (acid treatment) or immersed in a 5% by weight sodium hydroxide aqueous solution at 25°C for 60 minutes (NaOH treatment), the condition of each cured film was observed and evaluated in three stages according to the following criteria. Ta.
○: No change in appearance, film thickness change within 2% △: No change in appearance, but film thickness change exceeds 2% ×: Change in appearance

(Evaluation of curable resin composition: electrical reliability)
A test piece on which a cured film of the curable resin composition was formed was prepared in the same manner as in the gas generation evaluation above. 40 mg of the cured film of the test piece was scraped off and sampled, and this was immersed in 1 g of liquid crystal (MLC-6608 manufactured by Merck & Co., Ltd.) and held at 100°C for 72 hours.The voltage retention rate of the liquid crystal was measured. A three-level evaluation was performed based on the criteria.
○: Voltage holding rate is 95% or more △: Voltage holding rate is 90% or more and less than 95% ×: Voltage holding rate is less than 90%

(Evaluation of curable resin composition: transparency)
A test piece on which a cured film of the curable resin composition was formed was prepared in the same manner as in the gas generation evaluation above. The transmittance of the cured film at a wavelength of 400 nm was measured using a spectrophotometer, and evaluated in three stages based on the following criteria.
○: Transmittance is 95% or more △: Transmittance is 93% or more and less than 95% ×: Transmittance is less than 93%

(Evaluation of curable resin composition: light resistance)
The above-mentioned curable resin composition was applied onto a non-alkali glass substrate using a spin coater and dried on a 90° C. hot plate for 2 minutes to prepare a test piece. This operation was repeated several times, and the coating conditions (spin rotation speed) were adjusted so that a cured film with a thickness of 10 μm was obtained. Next, the test piece was baked in a hot air oven at 230°C for 30 minutes to produce a test piece on which a cured film of the curable resin composition was formed.
Thereafter, light irradiation was performed using a metering weather meter (M6T: manufactured by Suga Test Instruments Co., Ltd.) at an irradiation intensity of 0.5 kW/m ² at 1500 MJ/m ² . The discoloration of the cured product after irradiation was visually evaluated according to the following criteria.
◎: Yellowing cannot be visually confirmed at all.
○: Very slight yellowing can be visually confirmed.
△: Yellowing can be visually confirmed.
×: Obvious yellowing can be visually confirmed.

The evaluation results of each curable resin composition are shown in Tables 6 to 10.

The curable resin compositions (cured films) of Examples 1 to 48 simultaneously satisfy the flatness, low moisture absorption, and low gas emission properties required for the protective film of color filters, and also have high resistance. It can be seen that it has excellent chemical properties, electrical reliability, transparency, and light resistance.
On the other hand, the composition according to Comparative Example 1 uses siloxane epoxy resin a-1 with a high weight average molecular weight, so the flatness is particularly poor, and reactive groups tend to remain. The results were also poor in gas generation properties upon moisture absorption and chemical resistance (NMP), which are considered to be due to this.
In the compositions according to Comparative Examples 2 and 3, since siloxane epoxy resin a-2 or a-3 having a low weight average molecular weight is used, gas generation properties are particularly high, and chemical resistance (NMP, NaOH) is particularly high. ) The results were poor.
In the composition according to Comparative Example 4, since siloxane epoxy resin a-4 with a high epoxy equivalent was used, it is presumed that the content of reactive groups decreased and the curability and crosslinking density were insufficient. In particular, the results were poor in chemical resistance (NMP, NaOH).
The composition according to Comparative Example 5 uses a siloxane epoxy resin a-5 that has an epoxycyclohexyl group but no hydroxyl group, methoxy group, ethoxy group, or phenoxy group, and this resin has a predetermined T1 to T3 structure. Since the film does not have the following properties, the results were particularly poor in flatness, transparency, light resistance, and chemical resistance (NaOH).
In the compositions according to Comparative Examples 6 to 13, the amounts of non-siloxane epoxy compounds according to C-1 to C-4 were reduced by reducing the amount of resins a-1 to a-5 used in the above comparative examples. However, it has not been possible to fully satisfy each evaluation item.
Furthermore, in the compositions according to Comparative Examples 14 and 15, a siloxane epoxy resin was not used, and a non-siloxane epoxy compound according to C-1, C-2, or C-3 was used as a component corresponding to the resin. The results were particularly poor in gas-emitting properties and light resistance.

Claims (8)

A curable resin composition comprising a siloxane resin that satisfies the following (i) to ( iv ), and a curing agent and/or a photocationic initiator.
(i) In ^{the 29} Si-NMR spectrum, the structure T1 below shows a signal between -47 and -52 ppm, the structure T2 below shows a signal between -55 and -61 ppm, and the structure below shows a signal between -62 and -72 ppm. T3, and the signal area ratio is T1:T2:T3=0-1:1-10:1-100.
(ii) The weight average molecular weight is 750 to 20,000.
(iii) The molecular weight per reactive group included in (a) below is less than 350.

[In structures T1 to T3, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and X is the following (a) or (b), which may be the same or different. , in each structure at least one X is (a).
(a) Glycidyl group, 3,4-epoxycyclohexyl group, a group having a glycidyl group at the end of an organic group having 1 to 6 carbon atoms, or a 3,4-epoxycyclohexyl group at the end of an organic group having 1 to 6 carbon atoms a group with
(b) Organic group having 1 to 6 carbon atoms]
(iv) In the ²⁹ Si-NMR spectrum, it contains the following structure D1 showing a signal at -9 ppm to -13 ppm and the following structure D2 showing a signal at -15 ppm to -24 ppm.

[In structures D1 and D2, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and Y is the above (a) or (b), which may be the same or different in each structure. Good too. ] The curable resin composition according to claim 1, wherein the X contains a group having a 3,4-epoxycyclohexyl group at the end of an organic group having 1 to 6 carbon atoms. Claim 1, wherein the curing agent is one or more selected from the group consisting of polycarboxylic acids, anhydrides of polycarboxylic acids, and thermally decomposable esters of polycarboxylic acids. Or the curable resin composition according to 2 . The curable resin composition according to any one of claims 1 to 3 , wherein the solid content of the siloxane resin is 3% by mass or more and 99% by mass or less based on the total mass of solids. The curable resin composition according to any one of claims 1 to 4 , which contains a non-siloxane type compound that does not contain a siloxane skeleton and has an epoxy group or a polymerizable unsaturated bond. The curable resin according to claim 5 , wherein the non-siloxane compound that does not contain a siloxane skeleton and has an epoxy group or a polymerizable unsaturated bond is an epoxy compound represented by the following formula (4). Composition.

[In formula (4), Ar is a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms. Furthermore, some of the hydrogen atoms of the divalent aromatic hydrocarbon group represented by Ar may be substituted with a hydrocarbon group having 1 to 10 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a halogen group. good. The average value of l is 0 to 2. ] A cured product obtained by curing the curable resin composition according to any one of claims 1 to 6 . A method for producing a siloxane resin that satisfies the following (i) to ( iv ), comprising:
Hydrolysis or hydrolytic condensation of Si(X ₁ )(OR ₁ ) ₃ or hydrolysis or hydrolysis of Si(X ₁ )(OR ₁ ) ₃ and Si(X ₂ ) ₂ (OR ₄ ) ₂ A method for producing a siloxane resin, which comprises condensation.
[However, X ₁ is a group shown in (a) below, which may be the same or different, but at least has a 3,4-epoxycyclohexyl group at the end of an organic group having 1 to 6 carbon atoms. Contains a group with X ₂ is a group shown in (a) or (b) below, and may be the same or different, but has at least a group shown in (b). R ₁ and R ₄ are each independently an alkyl group having 1 to 3 carbon atoms or a phenyl group. ]
(i) In ^{the 29} Si-NMR spectrum, the structure T1 below shows a signal between -47 and -52 ppm, the structure T2 below shows a signal between -55 and -61 ppm, and the structure below shows a signal between -62 and -72 ppm. T3, and the signal area ratio is T1:T2:T3=0-1:1-10:1-100.
(ii) The weight average molecular weight is 750 to 20,000.
(iii) The molecular weight per reactive group included in (a) below is less than 350.

[In structures T1 to T3, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and X is the following (a) or (b), which may be the same or different. , in each structure at least one X is (a).
(a) Any reactive group selected from glycidyl group, 3,4-epoxycyclohexyl group, vinyl group, acroyl group, and methacryloyl group, or the above-mentioned reactive group at the end of an organic group having 1 to 6 carbon atoms. a group with
(b) Organic group having 1 to 6 carbon atoms]
(iv) In the ²⁹ Si-NMR spectrum, it contains the following structure D1 showing a signal at -9 ppm to -13 ppm and the following structure D2 showing a signal at -15 ppm to -24 ppm.

[In structures D1 and D2, R is a hydrogen group, methyl group, ethyl group, or phenyl group, and Y is the above (a) or (b), which may be the same or different in each structure. Good too. ]